Flexible tube.



UNITED STATES PATENT oEEIoE.

ERNST BECKMANN, DAHLEM, NEAR BERLIN, GERMANY, ASSIGNORATO OTWI-WERXE MIT IBESCHRANKTER HAFTUNG, F DELMENHORST, NEAR BREMEN, GERMANY, A

CORPORATION OF GERMANY.

FLEXIBLE TUBE.

Application med January 7, 191s. serial No. 210,738.

To all whom itmay concern. y

Be it known-that LERNSTQBECKMANN, a citizen .of the German-Empire, and residing at Dahlem, near Berlin, Germany, haveainf# vented certain new and useful Improvements in Flexible Tubes, `of lwhichthe following is l y p y -v y'-l-ing portlonso'fgthe tube of flexible fabric 'overlyingthe'r-urnsfof the inner wire. In

a speciica'tion.

Besides metallic Itubes'comprising overlapping spiral strips of metal andpas a' rule,

spiral packingl located between two such strips, flexible tubesrare knownl 1n which waterproof or gasproof materlalzis-arran ed' between two spiral wires. In known tu es of this type, however, the spiral wireswere wound so close together that the ladjacent'v turns abuttedz against=one another, so that the material located .,betweenthe. two layers of wire functioned-only vas-lpack'ing. This-"i material, or fabric'is generallyinqthe fo'rrnof" a strip laid longitudinally around the inner wire spiral, its slightly overlapping edges being joined together by someIwaterproo'f adhesive material. Such tubes, however, have, firstly, only a limited degree of flexibility, and, secondly, they have the disadvantage that particularly the joints of the packing material readily break open, especially when the tubing is being bent, in which event leaks are unavoidable. Further, the turns of the outer spiral Wire have a larger inner diameter than the outer diameter of the turns ,of the inner wire, and consequently the outer wire spiral can relatively readily shift onto the packing located between it and the inner spiral if special precautions against such shlfting are not taken as, e. g., by winding` in opposite directions. primary object of my invention is to provide an improved flexible tube of the type last described. To this end I arrange that the turns of the outer and inner spiral wires not only have equal or approximately equal diameters, but also are composed of approximately equally elastic material and are wound in the same direction at a predetermined but equal distance apart, so that the turnsof the outer wire lie spirally in the aps in the inner spiral and can press on the abrio located between the spiral wires, but so however that the fabric is pressed outward by the inner wire and inward by the outer, so that a. spirally undulating surface is imparted to the fabric itself, the turns of the inner wire having an outer circumferfence larger than the inner circumference of 'the turns of theouter wire and the turns of the outer wirethaving an outer circumfern fence' larger than the outer circumference of the turns'f the 4inner wire 'and serving to protect from abrasion the outwardly bulgthis manner I attain""thatl ythelayer of ,fabric Specification of Letters Patent. Patented Max- 19, 1918. t r- 'itself is no longer merel packing material,

but constitutes thejexterior limit of the tube as such; at the same time great flexibility ofthe tube is`as'sured,"and also the relative I' position of the fabric and the spiral wires is ynOtFiXed.` The fabric which'will generally bel laid in several layers around the inner.

` spiral wire need `not be stuck together at its broad overlappingedge; a perfectly tight pressure onfthefabric; Flor" proofing the material itself it tisirubbedlor impregnated,

before orafterthe manufacture ofy the tube, with a liquid or semi-solid packing or calking material that does not become rigid, in order to enable the slight displacement of the fabric at any time when the tube is bent without having to fear that the fabric or calking material will become brittle, as is unavoidable with packing that becomes hard or rigid. When thev described arrangement is adopted small leaks in the fabric itself can be remedied by applying layers of fabric at the defective places.

To these ends, the invention consists in the construction, arrangement. and combination of parts described hereinafter and pointed out in the claim. Y

One embodiment of the invention is represented by way of example in part sectional elevation in the accompanying drawing,

Referring t0 the drawing, the improved tube comprises an inner spiral wire 1, an outer spiral wire 2 and a layer of fabric or other suitable material 3 arranged between the turns of the two wires. The turns of the two spiral wires are of the same or approximately the same diameter, consist of approximately equally elastic material, and the two wires are wound in the same direction at a predetermined constant distance apart so that, as shown in the drawing, the turns of the outer wire lie in the gaps of the inner spiral wire. The fabric 3 which consists of waterproof or gasproof material, or is renlclosure Vis eflected owing tothe described e dered waterproof or gasproof, is laid on the inner spiral wire, preferably in such a manner that one or more layers are superposed on another, it being understood, however, that the various layers may consist of different materials. In all cases the ends of the layers will well overlap one another. After this layer of fabric has been arranged the outer spiral wire is laid in the gaps of the inner wire, so that the layer of fabric is pressed by the two wire spirals, the inner wire pressing outward and the outer inward. Consequently, the surface of the fabric acquires a spirally corrugated shape` as clearly shown in the drawing, and the fabric itself forms the wall of the tube.

Any metals of a proximately equal elasticity can be used or the two spiral wires. Also it is to be clearly understood that the invention isjn no way limited to -the use of textile fabrics for the layer 3, but that this layer may be composed of many other different kinds of materials, such as, for example, celluloid, cellon, rubber-like substances, gut-- tapercha-paper and leather which are Waterproof and gasproof in themselves. If ordinary fabrics permeable to gas and water are used, they will be impregnated with liquid or viscous agents, or they will have the same rubbed into them before or after the manufacture of the tube is complete. Rigid calking means or such means as become rigid must be avoided in order to prevent the calking means or the fabric becoming brittle.

Such a tube is very flexible and is always tight without the edges of the layer 3 being stuck down. The .usual connecting members can be suitably connected to the ends of the tube. If metal connections are employed they can be soldered to the wires of the tube.

I claim:

A flexible tube comprising a tube composed of flexible fabric, an inner spiral wire disposed inside said tube, and anouter spiral wire disposed outside said tube, said wires having turns of the same pitch, the turns of the inner wire being spaced a substantial distance from and disposed between the turns of the outer Wire substantially in alinement therewith, the turns of the inner wire having an outer circumference larger than the inner circumference of the turns of the outer wire and the turns of the outer wire having an outer circumference larger than the outer circumference of the turns of the inner wire and serving to protect from abrasion the outwardly bulged portions of the tube of flexible fabric overlying the turns of the inner wire.

In testimony whereof I have signed my name to this specification.

PROF. DR. ERNST BECICMANN. 

